Abstract
In the thermophilic biogas-producing microbial community, the genus Methanothermobacter was previously described to be frequently abundant. The aim of this study was to establish and analyze the genome sequence of the archaeal strain Methanothermobacter wolfeii SIV6 originating from a thermophilic industrial-scale biogas fermenter and compare it to related reference genomes. The circular chromosome has a size of 1,686,891 bases, featuring a GC content of 48.89%. Comparative analyses considering three completely sequenced Methanothermobacter strains revealed a core genome of 1494 coding sequences and 16 strain specific genes for M. wolfeii SIV6, which include glycosyltransferases and CRISPR/cas associated genes. Moreover, M. wolfeii SIV6 harbors all genes for the hydrogenotrophic methanogenesis pathway and genome-centered metatranscriptomics indicates the high metabolic activity of this strain, with 25.18% of all transcripts per million (TPM) belong to the hydrogenotrophic methanogenesis pathway and 18.02% of these TPM exclusively belonging to the mcr operon. This operon encodes the different subunits of the enzyme methyl-coenzyme M reductase (EC: 2.8.4.1), which catalyzes the final and rate-limiting step during methanogenesis. Finally, fragment recruitment of metagenomic reads from the thermophilic biogas fermenter on the SIV6 genome showed that the strain is abundant (1.2%) within the indigenous microbial community. Detailed analysis of the archaeal isolate M. wolfeii SIV6 indicates its role and function within the microbial community of the thermophilic biogas fermenter, towards a better understanding of the biogas production process and a microbial-based management of this complex process.
Highlights
Energy generation from renewable sources is an important part of the energy transition, taking climate protection into account
M. wolfeii SIV6 harbors all genes for the hydrogenotrophic methanogenesis pathway and genome-centered metatranscriptomics indicates the high metabolic activity of this strain, with 25.18% of all transcripts per million (TPM) belong to the hydrogenotrophic methanogenesis pathway and 18.02% of these TPM exclusively belonging to the mcr operon
Our analysis revealed that M. wolfeii SIV6 possesses genetic features that may mediate a better competitiveness of this strain in environments like thermophilic biogas fermenters
Summary
Energy generation from renewable sources is an important part of the energy transition, taking climate protection into account. Most of the German full-scale biogas fermenters are operated under mesophilic (37–42 ◦C) conditions; only few fermenters, i.e., 6%, perform the biomethanation under thermophilic (52–56 ◦C) conditions [8] In this context, studies addressing taxonomic analyses of the archaeal diversity within thermophilic biogas fermenters frequently described the occurrence of the genus Methanothermobacter [8,9,10,11], leading to the assumption that Methanothermobacter members contribute to a stable and well running thermophilic anaerobic digestion process. This study addresses the identification of genetic determinants potentially specifying competitiveness of Methanothermobacter species in the biogas fermenter habitat For this purpose, the genome sequence of the strain M. wolfeii SIV6, isolated from a German thermophilic production-scale biogas fermenter [8] utilizing maize silage and pig manure for biomethanation, was established and analyzed in detail. It is expected that insights from this study can be exploited to optimize the final phase, the methanogenesis, of the anaerobic digestion process
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
